Burgos M A, Sanmiguel-Rojas E, Martín-Alcántara A, Hidalgo-Martínez M
Departamento de Ingeniería Térmica y de Fluidos, Universidad Politécnica de Cartagena, Spain.
Int J Numer Method Biomed Eng. 2014 Mar;30(3):430-45. doi: 10.1002/cnm.2616. Epub 2013 Dec 5.
We analyse the effects of the air ambient temperature on the airflow across a Caucasian nasal cavity under different ambient temperatures using CFD simulations. A three-dimensional nasal model was constructed from high-resolution computed tomography images for a nasal cavity from a Caucasian male adult. An exhaustive parametric study was performed to analyse the laminar-compressible flow driven by two different pressure drops between the nostrils and the nasopharynx, which induced calm breathing flow rates ࣈ 5.7 L/min and ࣈ 11.3 L/min. The inlet air temperature covered the range - 10(o) C ⩽ To ⩽50(o) C. We observed that, keeping constant the wall temperature of the nasal cavity at 37(o) C, the ambient temperature affects mainly the airflow velocity into the valve region. Surprisingly, we found an excellent linear relationship between the ambient temperature and the air average temperature reached at different cross sections, independently of the pressure drop applied. Finally, we have also observed that the spatial evolution of the mean temperature data along the nasal cavity can be collapsed for all ambient temperatures analysed with the introduction of suitable dimensionless variables, and this evolution can be modelled with the help of hyperbolic functions, which are based on the heat exchanger theory.
我们使用计算流体动力学（CFD）模拟分析了不同环境温度下空气环境温度对白种人鼻腔内气流的影响。从一名成年白种男性的鼻腔高分辨率计算机断层扫描图像构建了三维鼻腔模型。进行了详尽的参数研究，以分析由鼻孔和鼻咽之间两种不同压降驱动的层流可压缩流，这两种压降分别导致平静呼吸流速为≤5.7升/分钟和≤11.3升/分钟。进气温度范围为−10(°)C≤To≤50(°)C。我们观察到，在将鼻腔壁温度保持在37(°)C不变的情况下，环境温度主要影响进入瓣膜区域的气流速度。令人惊讶的是，我们发现环境温度与在不同横截面处达到的空气平均温度之间存在极好的线性关系，与所施加的压降无关。最后，我们还观察到，通过引入合适的无量纲变量，对于所有分析的环境温度，沿鼻腔的平均温度数据的空间演变可以合并，并且这种演变可以借助基于热交换器理论的双曲线函数进行建模。
